Control method for electric vehicle and control device for electric vehicle

Abstract

A certain aspect of the present invention is a control method for an electric vehicle comprising a plurality of driving wheels and a plurality of electric motors that respectively generate driving forces to the plurality of driving wheels. In this control method, a vehicle body speed is estimated for each of the driving wheels on the basis of the rotation speeds of the electric motors. In addition, a driving wheel disturbance torque, which acts on each of the driving wheels, is estimated for each of the driving wheels on the basis of the vehicle body speed estimated for each of the driving wheels. Furthermore, on the basis of the driving wheel disturbance torque estimated for each of the driving wheels, a vehicle disturbance torque, which is a true disturbance torque acting on the entirety of the electric vehicle, is estimated, and, on the basis of this vehicle disturbance torque, respective torques to be output by the plurality of electric motors are controlled.

Description

[Technical Field]

[0001] The present invention relates to a control method for an electric vehicle and a control device for an electric vehicle. [Background technology]

[0002] JP2019-022339A discloses a motor control device that stops an electric vehicle using the driving force generated by a drive motor (hereinafter simply referred to as a motor). Specifically, the device estimates the disturbance torque acting on the motor, and when the vehicle is about to come to a stop, controls the output torque of the motor so that it matches the estimated disturbance torque. Summary of the Invention

[0003] Electric vehicles may use multiple electric motors for drive. In such electric vehicles using multiple motors, it may be difficult to accurately estimate the disturbance torque. For example, if there is a difference in the wheel loads of the multiple drive wheels connected to the electric motors due to factors such as road gradient, a non-negligible error may be superimposed on the estimated disturbance torque. Therefore, in electric vehicles using multiple motors, it may be impossible to accurately estimate the disturbance torque, and as a result, it may be impossible to properly control the electric vehicle.

[0004] An object of the present invention is to provide a control method for an electric vehicle that can accurately estimate disturbance torque and appropriately control an electric vehicle when the vehicle has multiple drive motors, and a control device for the electric vehicle.

[0005] One aspect of the present invention is a control method for an electric vehicle including a plurality of drive wheels and a plurality of electric motors that generate drive forces at each of the plurality of drive wheels. In this control method, a vehicle speed is estimated for each drive wheel based on the rotational speed of the electric motor. Furthermore, a drive wheel disturbance torque, which is a disturbance torque acting on the drive wheel, is estimated for each drive wheel based on the vehicle speed estimated for each drive wheel. Then, a vehicle disturbance torque, which is a true disturbance torque acting on the electric vehicle as a whole, is estimated based on the drive wheel disturbance torque estimated for each drive wheel, and torques to be output by each of the plurality of electric motors are controlled based on this vehicle disturbance torque. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a block diagram showing the configuration of an electric vehicle. [Figure 2] FIG. 2 is a flowchart showing the control executed by the motor controller. [Figure 3] FIG. 3 is a graph showing an example of an accelerator opening-torque table. [Figure 4] FIG. 4 is an explanatory diagram showing parameters used in the equations of motion of an electric vehicle. [Figure 5] FIG. 5 is a block diagram showing a configuration for executing stop control. [Figure 6] FIG. 6 is a block diagram showing the configuration of the vehicle speed estimation unit. [Figure 7] FIG. 7 is a block diagram showing the configuration of the disturbance torque estimating unit. [Figure 8] FIG. 8 is a block diagram showing the configuration of the distribution ratio calculation unit. [Figure 9] FIG. 9 is a block diagram showing a configuration for executing vibration suppression control. [Figure 10] FIG. 10 is a block diagram showing a vehicle model of an electric vehicle. [Figure 11] FIG. 11 is a block diagram of a feedforward compensator. [Figure 12]FIG. 12 is a time chart showing the transition of the torque command value, vehicle speed, longitudinal acceleration, and disturbance torque in the control of the comparative example and the present embodiment. [Figure 13] FIG. 13 is a block diagram showing the configuration of an electric vehicle according to a first modification. [Figure 14] FIG. 14 is a block diagram showing the configuration of an electric vehicle according to the second modification. [Figure 15] FIG. 15 is a block diagram showing the configuration of an electric vehicle according to the third modification. DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0008] [Embodiment] 1 is a block diagram showing the configuration of an electric vehicle 100. The electric vehicle 100 is an electric vehicle equipped with a plurality of drive wheels and a plurality of electric motors that generate drive forces for the plurality of drive wheels. In this embodiment, the electric vehicle 100 is a so-called four-wheel drive vehicle, and is equipped with front wheels 22 and rear wheels 32 that are drive wheels, and a front motor 21 and a rear motor 31 that generate drive forces for the drive wheels, respectively.

[0009] As shown in FIG. 1, the electric vehicle 100 includes a front drive system 11, a rear drive system 12, a battery 13, and a motor controller .

[0010] The front drive system 11 is a system that drives front wheels 22 by a front motor 21. In addition to the front motor 21 and the front wheels 22, the front drive system 11 is equipped with a front inverter 23, a rotation sensor 24, a current sensor 25, and the like.

[0011] The front motor 21 is, for example, a three-phase AC synchronous motor, and is driven by AC power input from the front inverter 23. The output torque of the front motor 21 generates torque (driving force) on the front wheels 22. Furthermore, when the drive shaft of the front motor 21 is rotated together with the front wheels 22, the front motor 21 generates so-called regenerative torque. This allows the front motor 21 to recover the kinetic energy of the electric vehicle 100 as electrical energy.

[0012] The front wheels 22 are a pair of drive wheels located at the front of the electric vehicle 100. The front wheels 22 are connected to the front motor 21 via a front reduction gear 26 and a drive shaft 27. In this embodiment, the front wheels 22 consist of a right front wheel and a left front wheel. However, since the right front wheel and the left front wheel are connected by the drive shaft 27 and driven integrally, in this embodiment, the right front wheel and the left front wheel are not distinguished from each other and are collectively referred to as the front wheels 22. Furthermore, the front wheels 22 are first drive wheels in comparison with the rear wheels 32, which are other drive wheels.

[0013] The front inverter 23 includes two pairs of switching elements for each phase of the front motor 21. The front inverter 23 opens and closes these switching elements in response to a PWM (Pulse Width Modulation) signal input from the motor controller 14. As a result, the front inverter 23 converts DC power supplied from the battery 13 into AC power and inputs it to the front motor 21 to drive the front motor 21. The switching elements that make up the front inverter 23 are power semiconductor elements, such as insulated gate bipolar transistors (IGBTs) and metal oxide semiconductor field effect transistors (MOS-FETs). During regenerative control, the front inverter 23 converts AC power generated by the front motor 21 into DC power and inputs it to the battery 13.

[0014] The rotation sensor 24 detects the rotor phase α of the front motor 21. f Detect the rotor phase α fis a so-called electrical angle [rad]. The rotation sensor 24 is, for example, a resolver or an encoder. The detected rotor phase α f is input to the motor controller 14.

[0015] The current sensor 25 detects the currents (hereinafter referred to as three-phase currents) i flowing through the respective phases of the front motor 21. uf ,i vf ,i wf The three-phase current i of the front motor 21 is detected. uf ,i vf ,i wf is input to the motor controller 14.

[0016] The rear drive system 12 is a system that drives rear wheels 32 by a rear motor 31, and is configured symmetrically to the front drive system 11. Therefore, in addition to the rear motor 31 and rear wheels 32, the rear drive system 12 also includes a rear inverter 33, a rotation sensor 34, a current sensor 35, a rear reduction gear 36, a drive shaft 37, etc. These components that make up the rear drive system 12 function in the same way as the components of the front drive system 11. In other words, the rear wheels 32 are a pair of drive wheels located at the rear of the electric vehicle 10. The rear wheels 32 consist of a right rear wheel and a left rear wheel, but in this embodiment, no distinction is made between these, and the right rear wheel and the left rear wheel are collectively referred to as the rear wheels 32. The rear wheels 32 are second drive wheels in comparison with the front wheels 22, which are other drive wheels. The rotor phase of the rear drive system 12 detected by the rotation sensor 34 is "α r The current flowing through each phase of the rear motor 31 detected by the current sensor 35 is "i ur ,i vr ,i wr "

[0017] The battery 13 is provided in common to the front drive system 11 and the rear drive system 12, and supplies power to drive the front motor 21 and the rear motor 31. During regenerative control, the battery 13 is charged by the regenerative power generated by the front motor 21 and the rear motor 31.

[0018] The motor controller 14 is a control device for the electric vehicle 100. The motor controller 14 is configured by one or more computers including, for example, a central processing unit (CPU), a read-only memory (ROM), a random access memory (RAM), and an input / output interface (I / O interface). The motor controller 14 is also programmed to control the front motor 21, the rear motor 31, and the like at a predetermined control cycle. For example, the motor controller 14 acquires various vehicle variables and generates PWM signals for driving the front motor 21 and the rear motor 31 based on these vehicle variables. The motor controller 14 then inputs the generated PWM signals to the front inverter 23 and the rear inverter 33, respectively, thereby driving the front motor 21 and the rear motor 31 in accordance with the vehicle variables.

[0019] The vehicle variables are parameters that represent the control state of the electric vehicle 10. For example, the motor controller 14 may use the rotor phase α of the front motor 21 as the vehicle variables. f and three-phase current i uf ,i vf ,i wf , the rotor phase α of the rear motor 31 r and three-phase current i ur ,i vr ,i wr In addition, the motor controller 14 acquires, for example, the accelerator opening A po , and the DC voltage V of the battery 13 dc etc. are acquired as vehicle variables. Accelerator opening A po is a parameter that represents the amount of accelerator pedal operation by the driver. po , and the DC voltage V of the battery 13 dc The vehicle variables such as the above can be detected appropriately as needed using, for example, a sensor (not shown) etc. Although the motor controller 14 of this embodiment acquires the vehicle variables directly from a sensor etc., the motor controller 14 can also acquire some or all of the vehicle variables from another controller (computer) (not shown).

[0020] In the electric vehicle 100 configured as described above, the motor controller 14 estimates disturbance torque, which is torque generated by a disturbance. Then, the motor controller 14 controls the torque to be output by the front motor 21 and the rear motor 31 based on the estimated disturbance torque, thereby controlling the operation of the electric vehicle 100. Below, as an example, a detailed description will be given of an example in which the estimated disturbance torque is used to allocate driving force to the front wheels 22 and the rear wheels 32, and to control the stopping of the electric vehicle 100.

[0021] Fig. 2 is a flowchart showing control executed by motor controller 14. As shown in Fig. 2, motor controller 14 executes input processing S11, first torque target value calculation S12, stop control S13, vibration damping control S14, current target value calculation S15, current control calculation S16, etc. That is, motor controller 14 is programmed to function as an input processing unit that executes input processing S11, a first torque target value calculation unit that executes first torque target value calculation S12, a stop control unit that executes stop control S13, and a vibration damping control unit that executes vibration damping control S14. Motor controller 14 is also programmed to function as a current target value calculation unit that executes current target value calculation S15, a current control calculation unit that executes current control calculation S16, etc.

[0022] The input process S11 is a process for acquiring or calculating vehicle variables and the like required for controlling the front motor 21 and the rear motor 31.

[0023] Specifically, in the input process S11, the motor controller 14 calculates the three-phase current i uf ,i vf ,i wf , and the three-phase current i of the rear motor 31 ur ,i vr ,i wr The three-phase current i of the front motor 21 is obtained. uf ,i vf ,i wfSince the sum of these is zero, the motor controller 14 can obtain, for example, the currents for two of these phases, and calculate the current for the remaining phase. This is because the three-phase current i ur ,i vr ,i wr The same is true for .

[0024] In addition, in the input process S11, the motor controller 14 determines the rotor phase α of the front motor 21. f , the rotor phase α of the rear motor 31 r , and the DC voltage V of the battery 13 dc Get.

[0025] In the input process S11, the motor controller 14 also receives, for example, the rotational angular velocity ω mf [rad / s], and the rotational angular velocity ω of the rear motor 31 mr [rad / s]. The rotational angular velocity ω of the front motor 21 is calculated. mf is the mechanical angular velocity, and the rotor phase α f is calculated by differentiating the rotational angular velocity ω of the rear motor 31 and dividing it by the number of pole pairs of the front motor 21. mr is the mechanical angular velocity, and the rotor phase α r is differentiated and divided by the number of pole pairs of the rear motor 31.

[0026] In this embodiment, the rotational angular velocity ω of the front motor 21 is used as a parameter representing the rotational speed of the electric motor provided in the electric vehicle 100. mf and the rotational angular velocity ω of the rear motor 31 mr However, for example, when the rotation speed N of the front motor 21 is mf [rpm], and the rotation speed N of the rear motor 31 mr The rotation speed N of the front motor 21 may be expressed as [rpm]. mf and the rotation speed N of the rear motor 31 mr is the rotational angular velocity ω of the front motor 21 mf and the rotational angular velocity ω of the rear motor 31 mrcan be calculated by multiplying each by a unit conversion coefficient (60 / 2π).

[0027] The first torque target value calculation S12 calculates a target value (hereinafter referred to as the first torque target value T) for the torque that should be output as a whole by the front motor 21 and the rear motor 31 in response to the driver's operation. m1 * In this embodiment, the motor controller 14 calculates the accelerator opening A po and the rotational angular velocity ω of the front motor 21 mf Based on this, the first torque target value T m1 * Calculate the following.

[0028] 3 is a graph showing an example of an accelerator opening-torque table. As shown in FIG. 3, the motor controller 14 calculates, for example, the accelerator opening A po and rotational angular velocity ω mf and the first torque target value T m1 * The motor controller 14 stores in advance an accelerator opening-torque table in which the accelerator opening A and the torque A are associated with each other based on experiments, simulations, etc. Therefore, the motor controller 14 can calculate the accelerator opening A and the torque B by referring to this accelerator opening-torque table. po and rotational angular velocity ω mf The first torque target value T m1 * Calculate the following.

[0029] In a normal driving state in which the stop control S13 is not executed, the first torque target value T m1 * is the front torque command value T mf1 * and rear torque command value T mr1 * The front torque command value T mf1 * is a command value that represents the target torque to be output by the front motor 21. mr1 * is a command value that represents the target torque to be output by the rear motor 31.mf1 * and rear torque command value T mr1 * First torque target value T m1 * Allocation ratio K f3 is the true disturbance torque acting on the electric vehicle 100 as a whole, "vehicle disturbance torque T d The vehicle disturbance torque T d The first torque target value T m1 * The details of the distribution will be described later together with the details of the stop control S13.

[0030] The stop control S13 (see FIG. 2) is a control for stopping the electric vehicle 100 and maintaining the stopped state by using the front motor 21, the rear motor 31, or both of them. Specifically, the motor controller 14 determines whether the electric vehicle 100 is in a state where it is about to stop. Then, when it is determined that the electric vehicle 100 is in a state where it is about to stop, the motor controller 14 executes the stop control S13. In addition, the motor controller 14 controls the vehicle disturbance torque T d and the estimated vehicle disturbance torque T d The second torque target value T is set based on m2 * When the stop control S13 is executed, the motor controller 14 calculates the second torque target value T m2 * The front torque command value T mf1 * and rear torque command value T mr1 * As a result, the motor controller 14 controls the front motor 21 and / or the rear motor 31 to stop the electric vehicle 100 and maintain the stopped state, regardless of the inclination of the road surface, etc. The front torque command value T mf1 * and rear torque command value T mr1 * Second torque target value T m2 * The distribution ratio of the vehicle disturbance torque T dThe stop control S13 will be described in detail later.

[0031] The vibration suppression control S14 is a process for suppressing vibrations occurring in the driving force transmission system. In the vibration suppression control S14, the motor controller 14 controls the front torque command value T mf1 * Based on this, the final torque command value to the front motor 21 (hereinafter referred to as the front final torque command value T mff * The front final torque command value T mff * In vibration suppression control S14, the motor controller 14 outputs the required torque from the front motor 21 while suppressing torsional vibrations of the drive shaft 27. Similarly, in vibration suppression control S14, the motor controller 14 determines the final torque command value (hereinafter referred to as the rear final torque command value Tmr1*) to the rear motor 31 based on the rear torque command value Tmr1*. mrf * The rear final torque command value T mrf * The vibration suppression control S14 suppresses torsional vibrations of the drive shaft 37 and outputs the required torque from the rear motor 31. Details of the vibration suppression control S14 will be described later.

[0032] The current target value calculation S15 is a process for calculating the target value of the current (hereinafter referred to as the current target value) to be input to the front motor 21 and the rear motor 31. The motor controller 14 calculates the current target value in the so-called dq-axis coordinate system. Specifically, the motor controller 14 calculates the front final torque command value T mff * , the rotational angular velocity ω of the front motor 21 mf , and the DC voltage V of the battery 13 dc Based on this, the dq-axis current target value i of the front motor 21 is calculated. df * ,i qf * Similarly, the motor controller 14 calculates the rear final torque command value T mrf * , the rotational angular velocity ω of the rear motor 31 mr, and the DC voltage V of the battery 13 dc Based on this, the dq-axis current target value i of the rear motor 31 is calculated. dr * ,i qr * Calculate the following.

[0033] The motor controller 14 calculates the front final torque command value T mff * , the rotational angular velocity ω of the front motor 21 mf , and the DC voltage V of the battery 13 dc and the dq-axis current target value i of the front motor 21. df * ,i qf * Similarly, the motor controller 14 stores a table in which the rear final torque command value T mrf * , the rotational angular velocity ω of the rear motor 31 mr , and the DC voltage V of the battery 13 dc and the dq-axis current target value i of the rear motor 31. dr * ,i qr * Therefore, the motor controller 14 can refer to these tables to obtain the d-axis current target value i of the front motor 21. df * ,i qf * , and the dq-axis current target value i of the rear motor 31 dr * ,i qr * Calculate the following.

[0034] The current control calculation S16 is a process for calculating the PWM signals for driving the front motor 21 and the rear motor 31. The motor controller 14 calculates the PWM signal for driving the front motor 21 as follows: First, the motor controller 14 calculates the three-phase current i uf ,i vf ,i wf and rotor phase αf Based on this, the dq axis current i df ,i qf Next, the motor controller 14 calculates the d-axis current target value i df * ,i qf * and dq axis current i df ,i qf Based on the deviation of df ,v qf At this time, the motor controller 14 may add a so-called non-interference control. In addition, the motor controller 14 calculates the dq-axis voltage command value v df ,v qf and rotor phase α f Based on this, the three-phase voltage command value v uf ,v vf ,v wf Then, the motor controller 14 calculates the three-phase voltage command value v uf ,v vf ,v wf and the DC voltage V of the battery 13 dc The PWM signal is calculated based on the calculated PWM signal. The switching elements of the front inverter 23 are opened and closed by the PWM signal calculated in this manner, thereby driving the front motor 21 to output the required torque. While the calculation of the PWM signal that drives the front motor 21 has been described above, the calculation of the PWM signal that drives the rear motor 31 is similar.

[0035] In the following, the stop control S13 and the first torque target value T m1 * The distribution of the vibration and the vibration suppression control S14 will be described in detail.

[0036] <Electric vehicle model> The stop control S13 and the vibration damping control S14 are executed based on a vehicle model of the electric vehicle 100. Specifically, in the stop control S13, a transfer characteristic G ωfV (s) and transfer characteristic G ωrV (s) is used. Transfer characteristic G ωfV(s) is the rotational angular velocity ω of the front motor 21 mf This is the transfer characteristic from the vehicle speed to the ωrV (s) is the rotational angular velocity ω of the rear motor 31 mr This is the transmission characteristic from the vehicle speed to the

[0037] In addition, in the vibration suppression control S14, the transfer characteristic G pff (s), transfer characteristic G rff (s) / G pff (s), transfer characteristic G prr (s) and transfer characteristic G rrr (s) / G prr (s) is used. Transfer characteristic G pff (s) is the torque output by the front motor 21 (hereinafter referred to as the front motor torque T mf ) from the rotational angular velocity ω of the front motor 21 mf The transfer characteristic is G rff (s) / G pff (s) is the transfer characteristic of the feedforward compensator that suppresses the torsional vibration of the drive shaft 27 in the front drive system 11. Transfer characteristic G prr (s) is the torque output by the rear motor 31 (hereinafter referred to as rear motor torque T mr ) from the rotational angular velocity ω of the rear motor 31 mr The transfer characteristic is G rrr (s) / G prr (s) is the transfer characteristic of the feedforward compensator that suppresses torsional vibration of the drive shaft 37 in the rear drive system 12.

[0038] Before describing the stop control S13 and the vibration damping control S14 in detail, a vehicle model of the electric vehicle 100 and its equation of motion, as well as each transfer characteristic used in the vibration damping control S14 will be described in particular. Each transfer characteristic used in the stop control S13 will be described in detail in the description of the stop control S13.

[0039] Fig. 4 is an explanatory diagram showing parameters used in the equations of motion of electric vehicle 100. When the driving force transmission system of electric vehicle 100 is modeled as shown in Fig. 4, the equations of motion of electric vehicle 100 are expressed by the following equations (1) to (11).

[0040]

number

[0041] The parameters in Figure 4 and the above equations of motion are as follows: "f" at the end of the auxiliary symbol (subscript) of each parameter indicates front, and "r" indicates rear. In addition, the "·" symbol above the parameters in (1) to (5) above represents time differentiation, and the "·" symbol between parameters in (1) to (9) above represents a product.

[0042] J mf ,J mr : Motor inertia J wf ,J wr : Drive shaft inertia (for one shaft) K df ,K dr : Torsional rigidity of the drive shaft K tf ,K tr : Coefficient of friction between the tire and road surface N f ,N r : Overall gear ratio r f ,r r : Tire load radius ω mf ,ω mr : Motor rotational angular velocity θ mf ,θ mr :Motor angle ω wf ,ω wr : Drive wheel angular velocity θ wf ,θ wr : Drive wheel angle T mf ,T mr :Motor torque T df ,T dr : Drive shaft torque F f ,F r : Driving force (for 2 axes) V: Vehicle speed M: Vehicle mass

[0043] Laplace transform equations (1) to (11) to obtain the front motor torque T mf from the rotational angular velocity ω of the front motor 21 mf Transfer characteristics G pff (s) is calculated using the following equations (12) and (13). The coefficients b0 to b6 and a0 to a6 in equation (13) are respectively expressed using the following equations (14) and (15). The parameter χ used in these coefficients b0 to b6 and a0 to a6 is 11 ~χ 24 and parameter δ 11 ~δ 44 are expressed by the following equations (16) and (17), respectively.

[0044]

number

[0045]

number

[0046]

number

[0047]

number

[0048]

number

[0049] The transfer characteristic G shown in equation (13) pff By examining the poles and zeros of (s), the transfer characteristic G pff (s) is expressed in the form of the following equation (18).

[0050]

number

[0051] In equation (18), α and α′, β and β′, ζ pr and ζ pr ′, ω pr and ω pr ' are very close values. Therefore, α = α', β = β', ζ pr =ζ pr ′ and ω pr =ω pr By performing pole-zero cancellation that approximates pff (s) is expressed in a quadratic / cubic format as shown in the following equation (19). In this way, in the vehicle model of the electric vehicle 100, the front motor torque T mf from the rotational angular velocity ω of the front motor 21 mf Transfer characteristics G pff (s) can be approximated in quadratic / cubic form.

[0052]

number

[0053] In addition, the above transfer characteristic G pff According to (s), the transfer characteristic G of the reference response that suppresses the torsional vibration caused by the drive shaft 27 of the front drive system 11 rff (s) can be expressed by the following equation (20).

[0054]

number

[0055] Therefore, in the front drive system 11, the feedforward compensator that suppresses the torsional vibration of the drive shaft 27 has a transfer characteristic G rff (s) / G pff (s)

[0056]

number

[0057] As above, rear motor torque T mr from the rotational angular velocity ω of the rear motor 31 mr Transfer characteristics G prr (s), etc. can be obtained. That is, the transfer characteristic G prr (s) is expressed by the following equations (22) and (23).

[0058]

number

[0059] In addition, in the rear drive system 12, the transmission characteristic G of the reference response that suppresses the torsional vibration of the drive shaft 37 is rrr (s) is expressed by the following equation (24).

[0060]

number

[0061] Therefore, in the rear drive system 12, the feedforward compensator that suppresses the torsional vibration of the drive shaft 37 has a transfer characteristic G rrr (s) / G prr (s)

[0062]

number

[0063] In addition, the rear motor torque T mr from the rotational angular velocity ω of the front motor 21 mf Transfer characteristics G prf (s) is as follows: That is, the Laplace transform of the equations (1) to (11) is performed to obtain the transfer characteristic G prf (s) is expressed by the following equations (26) and (27).

[0064]

number

[0065] Then, the transfer characteristic G expressed by equation (27) prf By examining the poles of (s), the transfer characteristic G prf It can be seen that (s) can be expressed by the following equation (28).

[0066]

number

[0067] Here, the poles α and β in equation (28) are located far from the origin and the dominant pole, and the transfer characteristic G prf Considering that the influence on (s) is small, the transfer characteristic G prf (s) can be approximated by the following equation (29).

[0068]

number

[0069] Furthermore, when the vibration suppression control algorithm of the rear drive system 12 is taken into consideration, the transfer characteristic G prf (s) is expressed by the following equation (30).

[0070]

number

[0071] Therefore, the rotational angular velocity ω of the front motor 21 mf From the reference response of the rear motor torque T mr The transmission characteristic G for suppressing the torsional vibration of the drive shaft 27 caused by the input of rrf (s) is expressed by the following equation (31).

[0072]

number

[0073] The control configuration of the electric vehicle 100 is substantially symmetrical between the front drive system 11 and the rear drive system 12, so the front motor torque T mf from the rotational angular velocity ω of the rear motor 31 mr Transfer characteristics G pfr (s) is expressed in the same format as equations (26) to (30). Also, the rotational angular velocity ω of the rear motor 31 is mr From the reference response of mf The transmission characteristic G for suppressing the torsional vibration of the drive shaft 37 caused by the input of rfr (s) is expressed in the same format as equation (31) above.

[0074] <Stop control> Fig. 5 is a block diagram showing a configuration for executing stop control S13. As shown in Fig. 5, motor controller 14 functions as a vehicle speed estimator 51, a disturbance torque estimator 52, a second torque target value calculator 53, a torque comparator 54, and a torque distributor 55.

[0075] The vehicle speed estimator 51 estimates the vehicle speed of the electric vehicle 100 for each drive wheel based on the rotation speed of the electric motor provided in the electric vehicle 100. In this embodiment, the vehicle speed estimator 51 estimates the rotation angular speed ω of the front motor 21 for the front wheels 22, which are drive wheels. mf The vehicle speed of the electric vehicle 100 is estimated based on the rotational angular velocity ω of the front motor 21. mf The vehicle speed estimated based on the fSimilarly, the vehicle speed estimation unit 51 estimates the rotational angular velocity ω of the rear motor 31 for the rear wheels 32, which are the driving wheels. mr The vehicle speed of the electric vehicle 100 is estimated based on the rotational angular velocity ω of the rear motor 31. mr The vehicle speed estimated based on the second estimated vehicle speed V r ^. First estimated vehicle speed V f ^ and second estimated vehicle speed V r is input to the disturbance torque estimation unit 52.

[0076] Furthermore, the vehicle speed estimation unit 51 calculates the first estimated vehicle speed V f ^ or second estimated vehicle speed V r ^Based on the vehicle speed feedback torque T ω Calculate the vehicle speed feedback torque T ω converges to zero as the vehicle speed of the electric vehicle 100 decreases. ω is input to the second torque target value calculation unit 53.

[0077] The disturbance torque estimation unit 52 calculates the front final torque command value T mff * (previous value), rear final torque command value T mrf * (previous value), first estimated vehicle speed V f ^, and the second estimated vehicle speed V r Based on the vehicle disturbance torque T d The disturbance torque is the torque generated by disturbances such as road gradient. d is a torque that can be considered to be a true disturbance torque acting on the electric vehicle 100 as a whole, which has a plurality of electric motors and a plurality of drive wheels. For example, even when there is a difference between the wheel loads of the front wheels 22 and the rear wheels 32 due to the road gradient, the vehicle disturbance torque T d is a torque vector that is determined by the road surface gradient. The error due to the difference in wheel load is reduced or suppressed, and the vehicle disturbance torque T d is input to the second torque target value calculation unit 53.

[0078] The disturbance torque estimation unit 52 estimates the vehicle disturbance torque T d Based on the above, the allocation ratio K f3 Calculate the distribution ratio K f3 The target value for the torque to be output by the front motor 21 and the rear motor 31 as a whole is expressed as the front torque command value T mf1 * and rear torque command value T mr1 * This is the ratio when allocating to the allocation ratio K f3 is set to a value, for example, greater than or equal to 0 and less than or equal to 1. In a normal running state in which the stop control S13 is not executed, the first torque target value T m1 * However, this distribution ratio K f3 In the state where the vehicle is about to stop and the stop control S13 is executed, the second torque target value T m2 * However, this distribution ratio K f3 The allocation ratio is K. f3 is input to the torque distribution unit 55.

[0079] The second torque target value calculation unit 53 calculates the vehicle speed feedback torque T ω and vehicle disturbance torque T d Based on this, the second torque target value T m2 * In this embodiment, the second torque target value calculation unit 53 is an adder, and calculates the vehicle body speed feedback torque T ω and vehicle disturbance torque T d By adding m2 * Calculate the following.

[0080] Second torque target value T m2 * is a determination criterion for determining whether or not the stop control S13 should be executed, i.e., whether or not the electric vehicle 100 is about to stop. In a state where the stop control S13 is executed and the electric vehicle 100 is about to stop, the first torque target value T m1 * Instead of the second torque target value T m2* is used as a target value for the torque to be output as a whole by the front motor 21 and the rear motor 31. Also, as described above, the vehicle body speed feedback torque T ω converges to zero as the vehicle speed of the electric vehicle 100 decreases, so the second torque target value T m2 * As the vehicle speed of the electric vehicle 100 decreases, the vehicle disturbance torque T d Therefore, when the electric vehicle 100 stops, the second torque target value T m2 * is the vehicle disturbance torque T d For example, on an uphill road, the second torque target value T m2 * On a downhill road, the second torque target value T m2 * On a flat road, the second torque target value T m2 * The second torque target value T m2 * is input to the torque comparison unit 54.

[0081] The torque comparison unit 54 compares the first torque target value T m1 * and the second torque target value T m2 * and, depending on the comparison result, the first torque target value T m1 * or the second torque target value T m2 * Either of these is set as the third torque target value T m3 * Specifically, the second torque target value T m2 * is the first torque target value T m1 * If the torque target value T m2 * The third torque target value T m3* On the other hand, the second torque target value T m2 * is the first torque target value T m1 * If the torque target value T m1 * The third torque target value T m3 * That is, the torque comparison unit 54 outputs the first torque target value T m1 * and the second torque target value T m2 * When the electric vehicle 100 is about to stop, the torque comparison unit 54 compares the second torque target value T m2 * The third torque target value T m3 * By outputting the signal as above, the stop control S13 is set to be executed.

[0082] The torque distribution unit 55 has a distribution ratio K f3 Based on this, the third torque target value T m3 * , the front torque command value T mf1 * and rear torque command value T mr1 * The torque distribution unit 55 includes a front torque command value calculation unit 56 and a rear torque command value calculation unit 57. In this embodiment, the front torque command value calculation unit 56 calculates a third torque target value T m3 * Allocation ratio K f3 The front torque command value T mf1 * The rear torque command value calculation unit 57 calculates the third torque target value T m3 * "1-K" f3 " is multiplied to obtain the rear torque command value T mr1 * Calculate the following.

[0083] When it is determined that the electric vehicle 100 is about to stop, the third torque target value T m3 * The actual situation is the second torque target value T m2 * Therefore, the torque distribution unit 55 substantially sets the second torque target value T m2 * The front torque command value T mf1 * and rear torque command value T mr1 * On the other hand, when the electric vehicle 100 is not in a state of about to stop and is in a normal traveling state, the third torque target value T m3 * The actual situation is the first torque target value T m1 * Therefore, the torque distribution unit 55 substantially calculates the first torque target value T m1 * The front torque command value T mf1 * and rear torque command value T mr1 * to be allocated to.

[0084] Allocation ratio K f3 As mentioned above, the vehicle disturbance torque T d This is set or changed based on the third torque target value T m3 * The actual situation is the first torque target value T m1 * and the second torque target value T m2 * That is, when it is determined that the electric vehicle 100 is about to stop, the estimated vehicle disturbance torque T d The allocation ratio K is set appropriately based on the above. f3 Therefore, the second torque target value T m2 *As a result, the stop control S13 is realized, which stops the electric vehicle 100 or maintains the stopped state by using the front motor 21 and the rear motor 31. Furthermore, even when the electric vehicle 100 is not in a state of about to stop but is in a normal running state, the estimated vehicle disturbance torque T d The allocation ratio K is set appropriately based on the above. f3 Therefore, the first torque target value T m1 * As a result, even in normal driving conditions, an appropriate front torque command value T mf1 * and rear torque command value T mr1 * As a result, a stable running state is achieved.

[0085] The specific configurations of the vehicle speed estimating section 51 and the disturbance torque estimating section 52 will be described in detail below.

[0086] Fig. 6 is a block diagram showing the configuration of the vehicle body speed estimation unit 51. As shown in Fig. 6, the vehicle body speed estimation unit 51 includes a first estimated vehicle body speed calculation unit 61, a second estimated vehicle body speed calculation unit 62, and a vehicle body speed feedback torque calculation unit 63.

[0087] The first estimated vehicle body speed calculation unit 61 calculates the rotational angular speed ω of the front motor 21. mf Based on this, the first estimated vehicle speed V f The first estimated vehicle body speed calculation unit 61 calculates, for example, the rotational angular speed ω of the front motor 21. mf from the transmission characteristic G ωfV In this embodiment, the transfer characteristic G ωfV (s) is the overall gear ratio N of the front drive system 11 as shown in the following equation (32): f and the dynamic tire load radius r of the front wheel 22 f and the constant K determined by ωfV The constant K ωfVThe overall gear ratio of the front drive system is 11N. f and the dynamic tire load radius r at the front wheel 22. f and is expressed by the following equation (33).

[0088]

number

[0089] The first estimated vehicle speed calculation unit 61 includes a transfer characteristic G ωfV (s) is the constant K ωfV Instead of configuring it as mf A filter expressed by the following equation (34) that approximates the transfer characteristic from the vehicle speed to the vehicle speed can be used.

[0090]

number

[0091] The second estimated vehicle speed calculation unit 62 calculates the rotational angular speed ω of the rear motor 31. mr Based on this, the second estimated vehicle speed V r The second estimated vehicle body speed calculation unit 62 calculates, for example, the rotational angular speed ω of the rear motor 31. mr from the vehicle speed at the drive shaft 37 of the rear drive system 12, ωrV In this embodiment, the transfer characteristic G ωrV (s) is the overall gear ratio N of the rear drive system 12 as shown in the following equation (35): r and the dynamic tire load radius r of the rear wheel 32 r and the constant K determined by ωrV The constant K ωrV The overall gear ratio of the rear drive system is 12N. r and the dynamic tire load radius r of the rear wheel 32 r and is expressed by the following equation (36).

[0092]

number

[0093] The second estimated vehicle speed calculation unit 62 includes a transfer characteristic G ωrV (s) is the constant K ωrV Instead of configuring it as mr A filter expressed by the following equation (37) that approximates the transfer characteristic from the vehicle speed to the vehicle speed can be used.

[0094]

number

[0095] The vehicle speed feedback torque calculation unit 63 calculates the first estimated vehicle speed V f ^ Gain K vref By multiplying by ω Calculate the gain K vref is determined in advance by adaptation based on experiments or simulations, etc. However, the gain K vref is negative (K vref <0). The vehicle speed feedback torque calculation unit 63 calculates the second estimated vehicle speed V r ^ Gain K vref By multiplying the vehicle speed feedback torque T ω may be calculated.

[0096] Fig. 7 is a block diagram showing the configuration of the disturbance torque estimation unit 52. As shown in Fig. 7, the disturbance torque estimation unit 52 includes a total torque calculation unit 71, a first estimated torque calculation unit 72, a second estimated torque calculation unit 73, a third estimated torque calculation unit 74, a first driving wheel disturbance torque estimation unit 75, a second driving wheel disturbance torque estimation unit 76, a selector 77, and a distribution ratio calculation unit 78.

[0097] The total torque calculation unit 71 calculates the total torque T m *In this embodiment, the total torque calculation unit 71 is an adder, and calculates the front final torque command value T mff * (previous value) and rear final torque command value T mrf * (previous value) to obtain the total torque T m * The front drive system 11 and the rear drive system 12 are used to calculate the overall gear ratio N f ,N r and dynamic tire load radius r f ,r r are different, the total torque calculation unit 71 calculates, for example, the rear final torque command value T mrf * is multiplied by a gain that converts it into the output shaft torque of the front motor 21. m * is input to the second estimated torque calculation unit 73 and the selector 77.

[0098] The total torque calculation unit 71 is an adder, and calculates the front final torque command value T mff * (previous value) and rear final torque command value T mrf * (previous value) by parameters different from the total torque T m * For example, the third torque target value T m3 * is one of the parameters that represents the sum of the torques to be output by the front wheels 22 and the rear wheels 32, the total torque calculation unit 71 calculates the third torque target value T m3 * and use this as the total torque T m * However, the front final torque command value T mff * and rear final torque command value T mrf * is the final command value after the vibration suppression control S14, the total torque calculation unit 71 calculates the front final torque command value T mff * and rear final torque command value T mrf *Using the total torque T m * As a result, the vehicle disturbance torque T calculated by the disturbance torque estimation unit 52 is d and distribution ratio K f3 The accuracy of

[0099] The first estimated torque calculation unit 72 calculates the first estimated vehicle speed V f First estimated torque T based on m1 ^ is calculated. First estimated torque T m1 ^ is the front motor torque T mf and rear motor torque T mr That is, the first estimated torque T m1 ^ represents the torque (hereinafter referred to as vehicle torque) corresponding to the driving force that should be exerted by the electric vehicle 100 as a whole. m1 ^ represents the vehicle torque on which errors due to changes in the wheel loads of the front wheels 22 and the rear wheels 32 are superimposed. In this embodiment, the first estimated torque calculation unit 72 calculates the vehicle response G r1 (s) and a low-pass filter H1(s) / G r1 That is, the first estimated torque calculation unit 72 calculates the first estimated vehicle speed V f ^, filter H1(s) / G r1 (s) to obtain the first estimated torque T m1 Calculates ^.

[0100] Vehicle response G r1 (s) is the equivalent mass M of the electric vehicle 100 v and the coefficient K Mf and is expressed by the following equation (38): v is the vehicle mass M of the electric vehicle 100 and the motor inertia J of the front motor 21 and the rear motor 31. mf ,J mr , inertia of the drive shafts 27, 37 (wheel inertia) J wf ,J wr etc., is expressed by the following equation (39). MfThe overall gear ratio of the front drive system is 11N. f and the tire load radius r of the front wheel 22 f is expressed by the following equation (40) using

[0101]

number

[0102] The low-pass filter H1(s) is used to filter the vehicle response G r1 The low-pass filter H1(s) is defined to be equal to or greater than the difference between the denominator order and the numerator order of (s). In this embodiment, the low-pass filter H1(s) is expressed by the following equation (41).

[0103]

number

[0104] The second estimated torque calculation unit 73 calculates the total torque T m * Based on this, the second estimated torque T m2 In this embodiment, the first estimated torque T m1 ^ and the third estimated torque T m3 In accordance with the method of estimating the total torque T m * is filtered by a low-pass filter H1(s) to obtain the second estimated torque T m2 ^ is calculated. Second estimated torque T m2 ^ represents the vehicle torque corresponding to the driving force that should be exerted by the electric vehicle 100 as a whole. However, the second estimated torque T m2 ^ represents the vehicle torque in an ideal state where errors due to changes in the wheel loads of the front wheels 22 and the rear wheels 32 are not superimposed. Therefore, the second estimated torque T m2 ^ is input to the first drive wheel disturbance torque estimating unit 75 and the second drive wheel disturbance torque estimating unit 76, and the first drive wheel disturbance torque T df and the second drive wheel disturbance torque T dr It is used as a reference value in the calculation of

[0105] The third estimated torque calculation unit 74 calculates the second estimated vehicle speed V r ^ Based on the third estimated torque T m3 ^ is calculated. The third estimated torque T m3 ^ is the front motor torque T mf and rear motor torque T mr That is, the third estimated torque T m3 represents the vehicle torque corresponding to the driving force that should be exerted by the electric vehicle 100 as a whole. m3 ^ represents the vehicle torque on which errors due to changes in the wheel loads of the front wheels 22 and the rear wheels 32 are superimposed. In this embodiment, the third estimated torque calculation unit 74 calculates the vehicle response G r2 (s) and a low-pass filter H1(s) / G r2 That is, the third estimated torque calculation unit 74 calculates the second estimated vehicle speed Vr^ by filtering H1(s) / G r2 (s) to obtain the third estimated torque T m3 Calculates ^.

[0106] Vehicle response G r2 (s) is the equivalent mass M of the electric vehicle 100 v and the coefficient K Mr and is expressed by the following equation (42): v is expressed by the above equation (39). Mr The overall gear ratio of the rear drive system is 12N. r and the tire load radius r of the rear wheel 32 r is expressed by the following equation (43).

[0107]

number

[0108] The first drive wheel disturbance torque estimator 75 estimates the first estimated torque T m1 ^ and the second estimated torque T m2 ^ Based on the first driving wheel disturbance torque T dfIn this embodiment, the first driving wheel disturbance torque estimator 75 is a subtractor, and calculates the second estimated torque T m2 ^ to the first estimated torque T m1 By subtracting ^, the disturbance torque T of the first driving wheel is calculated. df The driving wheel disturbance torque is an estimated value of the disturbance torque acting on the driving wheels. That is, the first driving wheel disturbance torque T df represents the disturbance torque estimated from the driving state of the front motor 21 (or the front wheels 22 or the front drive system 11). df is input to the selector 77 and the distribution ratio calculation unit 78.

[0109] The second drive wheel disturbance torque estimator 76 estimates the third estimated torque T m3 ^ and the second estimated torque T m2 ^ Based on the second driving wheel disturbance torque T dr In this embodiment, the second drive wheel disturbance torque estimator 76 is a subtractor, and calculates the second estimated torque T m2 ^ to the third estimated torque T m3 By subtracting ^, the disturbance torque T of the second driving wheel is calculated. dr Calculate the disturbance torque of the second driving wheel T dr represents the disturbance torque estimated from the driving state of the rear motor 31 (or the rear wheels 32 or the rear drive system 12). dr Ideally, the first driving wheel disturbance torque T df However, in reality, when a difference occurs in the wheel loads of the front wheels 22 and the rear wheels 32 due to the road gradient or the like, the first driving wheel disturbance torque T df and the disturbance torque of the second driving wheel T dr There is also a difference in the disturbance torque of the second driving wheel T dr is input to the selector 77 and the distribution ratio calculation unit 78.

[0110] Selector 77 selects the total torque T m * Based on this, the first driving wheel disturbance torque T df or the disturbance torque T of the second driving wheel drSelect one of the following and measure the vehicle disturbance torque T d Specifically, as shown in the following equation (44), the selector 77 outputs the total torque T m * When is a negative value, the first driving wheel disturbance torque T df and the disturbance torque of the second driving wheel T dr The minimum value of the vehicle disturbance torque T d On the other hand, the total torque T m * When is equal to or greater than zero (zero or a positive value), the selector 77 selects the first driving wheel disturbance torque T df and the disturbance torque of the second driving wheel T dr The maximum value of the vehicle disturbance torque T d That is, the selector 77 outputs the first driving wheel disturbance torque T estimated for the front wheels 22 and the rear wheels 32 as df and the second drive wheel disturbance torque T dr Based on this, the vehicle disturbance torque T d The selector 77 also functions as a slip detection unit that detects slippage of the front wheels 22 or the rear wheels 32 caused by changes in the wheel loads of the front wheels 22 and the rear wheels 32. The selector 77 also functions as a vehicle disturbance torque estimation unit that estimates the vehicle disturbance torque T d By reducing or suppressing the change in the vehicle disturbance torque T, the vehicle also functions as a slip suppression unit that suppresses slip of the front wheels 22 or rear wheels 32 caused by a change in the wheel load, etc. Note that slip refers to a difference in rotation speed between the front wheels 22 and rear wheels 32, which are the driving wheels. As described above, the vehicle disturbance torque T d is output to the second torque target value calculation unit 53, and the selector 77 also outputs the vehicle disturbance torque T d is output to the distribution ratio calculation unit 78.

[0111]

number

[0112] The disturbances acting on the electric vehicle 100 include air resistance, modeling errors due to the actual vehicle mass depending on the number of occupants and the load, tire rolling resistance, and gradient resistance. Of these, gradient resistance is dominant when the electric vehicle 100 is about to come to a stop. Although these disturbance factors differ depending on the specific driving conditions, the disturbance torque estimating unit 52 estimates the front torque command value T mf1 * , rear torque command value T mr1 * , and equivalent mass M V Based on this, the vehicle disturbance torque T d Therefore, these disturbance factors can be estimated collectively. d By controlling the output torque of the front motor 21 and the rear motor 31 based on the above, the electric vehicle 100 can be controlled accurately under various driving conditions.

[0113] The distribution ratio calculation unit 78 calculates the first drive wheel disturbance torque T df and the second drive wheel disturbance torque T dr and the vehicle disturbance torque T d Based on this, the allocation ratio K f3 Calculate the following.

[0114] Fig. 8 is a block diagram showing the configuration of the allocation ratio calculation unit 78. As shown in Fig. 8, the allocation ratio calculation unit 78 includes a first allocation ratio calculation unit 81, a second allocation ratio calculation unit 82, and a third allocation ratio calculation unit 83.

[0115] The first distribution ratio calculation unit 81 calculates the vehicle disturbance torque T d Based on the first allocation ratio K f1 Calculate the first distribution ratio K f1 is a basic distribution ratio of the driving force in an ideal state where there is no change in the wheel load of the driving wheels. In this embodiment, the first distribution ratio calculation unit 81 calculates the vehicle disturbance torque T d Transmission characteristics G from the driving force distribution ratio dN1 (s), the first distribution ratio K is calculated according to the following equation (45): f1 Calculate the transfer characteristic G dN1(s) is the coefficient K dN1 Using the coefficient K, it is expressed by the following equation (46). dN1 is determined in advance by adaptation based on experiments, simulations, etc.

[0116]

number

[0117] The second distribution ratio calculation unit 82 is configured by, for example, a first calculation unit 84 and a second calculation unit 85. The first calculation unit 84 calculates the first driving wheel disturbance torque T df and the disturbance torque of the second driving wheel T dr The deviation of the disturbance torque deviation ΔT d In this embodiment, the first calculation unit 84 is a driving wheel disturbance torque deviation calculation unit that calculates the first driving wheel disturbance torque T df to the disturbance torque T of the second driving wheel dr By subtracting the disturbance torque deviation ΔT d The second calculation unit 85 calculates the driving wheel disturbance torque deviation ΔT d Transmission characteristics G from the driving force distribution ratio dN2 (s), the second distribution ratio K is calculated according to the following equation (47): f2 In this embodiment, the transfer characteristic G dN2 (s) is the coefficient K determined in advance by fitting based on experiments or simulations. dN2 The second distribution ratio K f2 is the basic allocation ratio, the first allocation ratio K f1 is the distribution ratio that functions as a correction or adjustment term for the first drive wheel disturbance torque T df and the disturbance torque of the second driving wheel T dr This works when there is a difference between

[0118]

number

[0119] In addition, the transfer characteristic G dN2(s) may be a first-order lag transfer characteristic as shown in the following equation (49).

[0120]

number

[0121] The third distribution ratio calculation unit 83 calculates the first distribution ratio K f1 and the second distribution ratio K f2 Based on this, the final distribution ratio of driving force K f3 In this embodiment, the third distribution ratio calculation unit 83 is a subtractor, and calculates the first distribution ratio K f1 From the second distribution ratio K f2 By subtracting the distribution ratio K f3 As described above, in the electric vehicle 100, this distribution ratio K f3 According to the above, the third torque target value T m3 * is the front torque command value T mf1 * and rear torque command value T mr1 * Thus, the driving force is distributed to the front wheels 22 and the rear wheels 32. Therefore, even if there is a difference in the wheel load between the front wheels 22 and the rear wheels 32 due to, for example, the road gradient, the driving force appropriate for the situation is distributed to the front wheels 22 and the rear wheels 32.

[0122] <Vibration control> 9 is a block diagram showing a configuration for executing vibration suppression control S 14. As shown in FIG. 9, the motor controller 14 functions as a feedforward compensator 91 and a feedback compensator 92.

[0123] The feedforward compensator 91 calculates the front torque command value T mf1 * and rear torque command value T mr1 * Based on this, the second front torque command value T mf2 * and the second rear torque command value T mr2 *and the estimated rotational angular velocity ω of the front motor 21. mf ^ and the estimated rotational angular velocity ω of the rear motor 31 mr ^ and , and calculate the second front torque command value T mf2 * is the front torque command value after feedforward compensation. The second rear torque command value T mr2 * is the rear torque command value after feedforward compensation.

[0124] Fig. 10 is a block diagram showing a vehicle model of electric vehicle 100. Details of the vehicle model shown in Fig. 10 have been described above. Fig. 11 is a block diagram of feedforward compensator 91. As shown in Figs. 10 and 11, feedforward compensator 91 has a configuration in which torsional vibration compensation units 101 and 102 and dead zone models 103 and 104 are added to the vehicle model of electric vehicle 100.

[0125] The torsional vibration compensation unit 101 calculates the front torque command value T mf1 * The torsional vibration compensation unit 101 compensates for the torsional vibration of the drive shaft 27 in the front drive system 11 with respect to the estimated torsional angular velocity φ f The torsional vibration compensation unit 101 calculates the torsional vibration compensation value (k1φ f ^) is the front torque command value T mf1 * The second front torque command value T mf2 * Calculate the following.

[0126] Front motor torque T mf to the torque of the drive shaft 27 (hereinafter referred to as the drive shaft torque T DSf When designing the transfer characteristic up to ζ, so that the attenuation coefficient appearing in the denominator is "1", the gain k1 is expressed by the following equation (50). pf is the damping coefficient of the torque transmission system in the front drive system 11.pf is the natural vibration frequency of the torque transmission system in the front drive system 11. tf is the front motor torque T mf to drive shaft torque T DSf The steady-state gain is

[0127]

number

[0128] The torsional vibration compensation unit 102 calculates the rear torque command value T mr1 * The torsional vibration compensation unit 102 compensates for the torsional vibration of the drive shaft 37 in the rear drive system 12 with respect to the estimated torsional angular velocity φ r The torsional vibration compensation unit 102 calculates the torsional vibration compensation value (k2φ r ^) is the rear torque command value T mr1 * By subtracting from the second rear torque command value T mr2 * Calculate the following.

[0129] The gain k2 is set in the same manner as the gain k1. That is, the rear motor torque T mr to the torque of the drive shaft 37 (hereinafter referred to as the drive shaft torque T DSr When designing the transfer characteristic up to ζ, so that the attenuation coefficient appearing in the denominator is "1", the gain k2 is expressed by the following equation (51). pr is the damping coefficient of the torque transmission system in the rear drive system 12. pr is the natural vibration frequency of the torque transmission system in the rear drive system 12. tr is the rear motor torque T mr to drive shaft torque T DSr The steady-state gain is

[0130]

number

[0131] The dead zone model 103 is a model that simulates the backlash characteristics of the gears used in the front drive system 11. The dead zone model 103 is expressed by the following equation (52). Similarly, the dead zone model 104 is a model that simulates the backlash characteristics of the gears used in the rear drive system 12. The dead zone model 104 is expressed by the following equation (53). Note that θ df and θ dr is the twist angle, and θ deadf and θ deadr is the angle of the dead zone (backlash characteristic).

[0132]

number

[0133] The feedback compensator 92 (see FIG. 9) calculates the second front torque command value T mf2 * , the estimated rotational angular velocity ω of the front motor 21 mf ^, and the actual rotational angular velocity ω of the front motor 21 mf Based on this, the front final torque command value T mff * The feedback compensator 92 calculates the second rear torque command value T mr2 * , the estimated rotational angular velocity ω of the rear motor 31 mr ^, and the actual rotational angular velocity ω of the rear motor 31 mr Based on this, the rear final torque command value T mrf * Specifically, the feedback compensator 92 calculates the front final torque command value T mff * a first feedback calculation unit 93 that calculates the rear final torque command value T mrf * and a second feedback calculation unit 94 that calculates the following.

[0134] The first feedback calculation unit 93 includes a deviation calculation unit 93a, a feedback torque calculation unit 93b, and a compensation unit 93c. The deviation calculation unit 93a calculates an estimated rotational angular velocity ω of the front motor 21. mf ^ and the actual rotational angular velocity ω mf Deviation Δω mf In this embodiment, the deviation calculation unit 93a calculates the estimated rotational angular velocity ω mf ^ to the actual rotational angular velocity ω mf By subtracting the deviation Δω mf The feedback torque calculation unit 93b calculates the deviation Δω mf Based on this, the second front torque command value T mf2 * Feedback torque T mf3 * The compensation unit 93c calculates the second front torque command value T mf2 * and feedback torque T mf3 * Based on this, the front final torque command value T mff * In this embodiment, the compensation unit 93c calculates the second front torque command value T mf2 * to the feedback torque T mf3 * By adding mff * Calculate the following.

[0135] The feedback torque calculation unit 93b uses a band-pass filter H f (s) and the aforementioned transfer characteristic G pff (s) using filter H f (s) / G pff (s) is composed of the bandpass filter H f (s) is set so that the attenuation characteristics of the low-pass and high-pass sides are nearly identical and the torsional resonance frequency of the front drive system 11 is located at the center of the pass band on the logarithmic axis. When the filter is composed of a first-order low-pass filter and a first-order high-pass filter, the band-pass filter H f(s) is expressed by the following equation (54). The time constant and cutoff frequency are as shown in the following equations (55) to (58). pf " is the torsional resonance frequency of the front drive system 11. f " is a coefficient that is predetermined by fitting based on experiments or simulations.

[0136]

number

[0137] The second feedback calculation unit 94 is configured in the same manner as the first feedback calculation unit 93. That is, the second feedback calculation unit 94 includes a deviation calculation unit 94a, a feedback torque calculation unit 94b, and a compensation unit 94c. The deviation calculation unit 94a calculates the estimated rotational angular velocity ω of the rear motor 31. mr ^ and the actual rotational angular velocity ω mr Deviation Δω mr The feedback torque calculation unit 94b calculates the deviation Δω mr Based on this, the second rear torque command value T mr2 * Feedback torque T mr3 * The compensation unit 94c calculates the second rear torque command value T mr2 * and feedback torque T mr3 * Based on this, the rear final torque command value T mrf * Calculate the following.

[0138] The feedback torque calculation unit 94b uses a band-pass filter H r (s) and the aforementioned transfer characteristic G prr (s) using filter H r (s) / G prr (s) is composed of the bandpass filter H r(s) is set so that the attenuation characteristics of the low-pass and high-pass sides are nearly identical, and the torsional resonance frequency of the rear drive system 12 is located at the center of the pass band on the logarithmic axis. When configured with a first-order low-pass filter and a first-order high-pass filter, the band-pass filter H r (s) is expressed by the following equation (59). The time constant and cutoff frequency are as shown in the following equations (60) to (63). pr " is the torsional resonance frequency of the rear drive system 12. r " is a coefficient that is predetermined by fitting based on experiments or simulations.

[0139]

number

[0140] <effect> The operation of the electric vehicle 100 according to this embodiment configured as described above will be described below in comparison with a comparative example. Here, as an example, a scene will be described in which the stop control S13 is executed on an uphill road with a constant gradient and a low friction road surface. In the comparative example, the front motor torque T mf and rear motor torque T mr The disturbance torque (vehicle disturbance torque T d ) and executes stop control S13 based on the estimated value. In the comparative example, the distribution ratio of the driving force to the front wheels 22 and the rear wheels 32 is a predetermined fixed value (here, 1:1).

[0141] FIG. 12 shows the torque command value T * , vehicle speed V, longitudinal acceleration A c , and disturbance torque T d 12(A) to 12(D) are time charts showing the transition of the torque command value T * , vehicle speed V, longitudinal acceleration A c , and disturbance torque T d12(E) to 12(H) show the transition of the torque command value T * (Front final torque command value T mff * and rear final torque command value T mrf * ), vehicle speed V, longitudinal acceleration A c , and disturbance torque T d 12(C) and 12(G) show the transition of the vehicle disturbance torque. c * " is the longitudinal acceleration that balances with the road gradient. "T d * " is the disturbance torque due to the road surface gradient. Time t1 in Figures 12(A) to 12(H) is the time when it is determined that the vehicle is about to stop and the stop control S13 is started. Also, it is assumed that slippage occurs between time t1 and time t2 due to a change in the wheel load of the front wheels 22 and the rear wheels 32.

[0142] As shown in Figures 12(A) to 12(H), when the stop control S13 is started at time t1 due to deceleration from time t0, as shown in Figures 12(B) and 12(F), the vehicle speed V changes asymptotically toward approximately zero toward time t3 due to the stop control S13. Then, as shown in Figures 12(D) and 12(H), in both the control of this embodiment and the control of the comparative example, the estimated vehicle disturbance torque T d is roughly the disturbance torque T due to the road gradient. d * asymptotically approaches .

[0143] At this time, in the control of the comparative example, as shown in FIG. 12(D), slippage occurs due to a change in the wheel load of the front wheels 22 and the rear wheels 32, and after time t2, the estimated vehicle disturbance torque T d is the actual disturbance torque T due to the road gradient d * Therefore, in the control of the comparative example, as shown in FIG. 12(C), after the start of the stop control S13, the longitudinal acceleration A c is the longitudinal acceleration A that balances with the road gradient c* As a result, as shown in Fig. 12(B), under the control of the comparative example, after the electric vehicle 100 has come to a temporary halt, it is unable to maintain the stopped state and slides down.

[0144] On the other hand, in the control of this embodiment, when slippage occurs due to a change in the wheel load of the front wheels 22 and the rear wheels 32, as shown in FIG. 12(H), the vehicle disturbance torque T d Therefore, even after time t2, the actual state of the estimated vehicle disturbance torque T d The accuracy of the vehicle disturbance torque T d is the actual disturbance torque T due to the road gradient d * 12(E), appropriate driving force is distributed to the front wheels 22 and the rear wheels 32 in accordance with changes in the wheel loads of the front wheels 22 and the rear wheels 32. Therefore, in the control of this embodiment, as shown in FIG. 12(G), after the start of the stop control S13, the longitudinal acceleration A c is the longitudinal acceleration A that balances with the road gradient. c * 12(F), the electric vehicle 100 is stopped by the stop control S13 and can be maintained in this stopped state.

[0145] In the above embodiment, an electric vehicle 100 having a front drive system 11 and a rear drive system 12, with the front wheels 22 and rear wheels 32 being drive wheels, has been described as an example, but the present invention can also be suitably implemented in electric vehicles of other configurations. In the following modifications, the configuration of an electric vehicle of another configuration in which the present invention can be suitably implemented will be described. However, in each modification, the same reference numerals will be used to designate components similar to those in the above embodiment or other modifications, and a description thereof will be omitted. Furthermore, in each modification, the vehicle disturbance torque T d The specific control aspects based on this are the same as those in the above embodiment.

[0146] [First Modification] 13 is a block diagram showing the configuration of an electric vehicle 130 according to a first modification. The electric vehicle 130 includes a right rear-wheel drive system 131 that drives a right rear wheel 32R with a first rear motor 31R, and a left rear-wheel drive system 132 that drives a left rear wheel 32L with a second rear motor 31L. That is, the electric vehicle 130 includes the right rear wheel 32R and the left rear wheel 32L, which are drive wheels that are driven independently of each other, and the first rear motor 31R and the second rear motor 31L that generate drive forces for these drive wheels, respectively.

[0147] The right rear-wheel drive system 131 includes a right rear wheel 32R and a first rear motor 31R, as well as a first rear inverter 33R, a rotation sensor 34R, a current sensor 35R, a first rear reduction gear 36R, and a drive shaft 37R. The left rear-wheel drive system 132 includes a left rear wheel 32L and a second rear motor 31L, as well as a second rear inverter 33L, a rotation sensor 34R, a current sensor 35R, a second rear reduction gear 36L, and a drive shaft 37L. The functions of these components are similar to those of the corresponding components of the front drive system 11 or the rear drive system 12 of the above-described embodiment. Therefore, the motor controller 14 controls the three-phase current i of the first rear motor 31R. ur1 ,i vr1 ,i wr1 and rotor phase α r1 , and the three-phase current i of the second rear motor 31L ur2 ,i vr2 ,i wr2 and rotor phase α r2 By using the above, it is possible to execute the same control as in the above embodiment for the right rear wheel drive system 131 and the left rear wheel drive system 132.

[0148] In the first modified example, the electric vehicle 130 is described as having the right rear wheel 32R and the left rear wheel 32L as drive wheels, but the present invention can also be suitably implemented in an electric vehicle having the right front wheel and the right rear wheel as drive wheels.

[0149] [Second Modification] Fig. 14 is a block diagram showing the configuration of an electric vehicle 140 according to a second modified example. As shown in Fig. 14, the electric vehicle 140 has front wheels 22, a right rear wheel 32R, and a left rear wheel 32L as drive wheels. The configuration of the front drive system 11 that drives the front wheels 22 is the same as in the above embodiment. Furthermore, the configurations of the right rear wheel drive system 131 that drives the right rear wheel 32R and the left rear wheel drive system 132 that drives the left rear wheel 32L are the same as in the above first modified example.

[0150] In the electric vehicle 140, the motor controller 14 can execute the same control as in the above embodiment by using the three-phase currents and rotor phases of the front motor 21, the first rear motor 31R, and the second rear motor 31L. Specifically, the motor controller 14 calculates the drive wheel disturbance torque for each of the front wheels 22, the right rear wheel 32R, and the left rear wheel 32L, and calculates the minimum or maximum value of these as the vehicle disturbance torque T d By doing so, it is possible to execute the same control as in the above embodiment.

[0151] Here, the example described is an electric vehicle 140 in which the front wheels 22, the right rear wheel 32R, and the left rear wheel 32L are each the drive wheels, but the present invention can also be suitably implemented in an electric vehicle in which the right front wheel 22R, the left front wheel 22L, and the rear wheels 32 are the drive wheels.

[0152] [Third Modification] Fig. 15 is a block diagram showing the configuration of an electric vehicle 150 according to a third modification. As shown in Fig. 15, electric vehicle 150 has right front wheel 22R, left front wheel 22L, right rear wheel 32R, and left rear wheel 32L as drive wheels. Therefore, electric vehicle 150 is equipped with right front wheel drive system 151, left front wheel drive system 152, right rear wheel drive system 131, and left rear wheel drive system 132.

[0153] The right front-wheel drive system 151 drives the right front wheel 22R using a first front motor 21R. In addition to the right front wheel 22R and the first front motor 21R, the right front-wheel drive system 151 also includes a first front inverter 23R, a rotation sensor 24R, a current sensor 25R, a first front reduction gear 26R, and a drive shaft 27R. The left front-wheel drive system 152 drives the left front wheel 22L using a second front motor 21L. In addition to the left front wheel 22L and the second front motor 21L, the left front-wheel drive system 152 also includes a second front inverter 23L, a rotation sensor 24L, a current sensor 25L, a first front reduction gear 26L, and a drive shaft 27L. The functions of these components are similar to the functions of the corresponding components of the front drive system 11 or rear drive system 12 of the above-mentioned embodiment. The three-phase current i of the first front motor 21R uf1 ,i vf1 ,i wf1 and rotor phase α f1 , and the three-phase current i of the second front motor 21L uf2 ,i vf2 ,i wf2 and rotor phase α f2 are input to the motor controller 14. The right rear wheel drive system 131 and the left rear wheel drive system 132 have the same configuration as the first or second modified example.

[0154] In the electric vehicle 150, the motor controller 14 can perform the same control as in the above embodiment by using the three-phase currents and rotor phases of the first front motor 21R, the second front motor 21L, the first rear motor 31R, and the second rear motor 31L. Specifically, the motor controller 14 calculates the drive wheel disturbance torque for each of the right front wheel 22R, the left front wheel 22L, the right rear wheel 32R, and the left rear wheel 32L, and calculates the minimum or maximum value of these as the vehicle disturbance torque T d By doing so, it is possible to execute the same control as in the above embodiment.

[0155] Here, the example described is an electric vehicle 150 in which the right front wheel 22R, the left front wheel 22L, the right rear wheel 32R, and the left rear wheel 32L are each driven wheels, but the present invention can also be suitably implemented in an electric vehicle having five or more driven wheels.

[0156] In the above embodiment and each modification, the vehicle disturbance torque T d Based on the distribution ratio K f3 The stop control S13 is performed while adjusting the vehicle disturbance torque T d Therefore, the vehicle disturbance torque T d is the stop control S13 (second torque target value T m2 * It is not used for the calculation of the distribution ratio K f3 In addition, the vehicle disturbance torque T estimated in the above embodiment and each modification can be used only for adjusting the d is not used to adjust the distribution ratio Kf3, but is used in the stop control S13 (second torque target value T m2 * Furthermore, the vehicle disturbance torque T d is the distribution ratio K f3 and the stop control S13 (the second torque target value T m2 * It can also be used for controls other than the calculation of

[0157] The configurations for executing the vibration suppression control S14 in the above-described embodiment and each modified example are merely examples. The vibration suppression control S14 can be executed by feedforward control and feedback control in forms different from the feedforward compensator 91 and feedback compensator 92 described in the above-described embodiment, etc.

[0158] As described above, the control method for an electric vehicle according to the above-described embodiment and each of the modified examples is a control method for an electric vehicle (e.g., electric vehicle 100) that includes a plurality of drive wheels (e.g., front wheels 22 and rear wheels 32) and a plurality of electric motors (e.g., front motor 21 and rear motor 31) that generate drive forces for the plurality of drive wheels. In this control method, the rotational speed (e.g., rotational angular velocity ω mf ,ω mv ), based on the vehicle speed (for example, the first estimated vehicle speed V f ^ and second estimated vehicle speed V r ^) is estimated for each drive wheel. In addition, based on the vehicle speed estimated for each drive wheel, a drive wheel disturbance torque (for example, a first drive wheel disturbance torque T df and the second drive wheel disturbance torque T dr ) is estimated for each drive wheel. Then, based on the drive wheel disturbance torque estimated for each drive wheel, a vehicle disturbance torque T d is estimated, and this vehicle disturbance torque T d Based on this, the torque to be output from each of the plurality of electric motors is controlled.

[0159] In this way, the disturbance torque (drive wheel disturbance torque) is estimated for each drive wheel, and the true disturbance torque (vehicle disturbance torque T d ) can be accurately estimated regardless of changes in the wheel load of the driving wheels. Therefore, the vehicle disturbance torque T d By controlling the output torque of each electric motor based on the above, the electric vehicle can be controlled accurately regardless of changes in the wheel load of the drive wheels.

[0160] In the above embodiment and each modified example, in particular, the torque to be output by a plurality of drive wheels (for example, the front final torque command value T mff * and rear final torque command value T mrf * ) and the total torque T m * is calculated. Then, this total torque Tm * Based on this, the driving wheel disturbance torque and the vehicle disturbance torque T d is calculated.

[0161] Thus, the total torque T m * Based on the driving wheel disturbance torque and vehicle disturbance torque T d By calculating the above, the driving wheel disturbance torque and the vehicle disturbance torque T d is estimated particularly accurately. More specifically, the total torque T m * The disturbance torque of the drive wheels can be calculated accurately by using the total torque T m * By using this accurate driving wheel disturbance torque, the vehicle disturbance torque T d is a particularly accurate representation of the true disturbance torque. Therefore, the total torque T m * Based on the driving wheel disturbance torque and vehicle disturbance torque T d By calculating the above, the electric vehicle can be controlled particularly accurately regardless of changes in the wheel load of the drive wheels.

[0162] In the above embodiment and modified examples, the vehicle speed estimated for each drive wheel (for example, the first estimated vehicle speed V f ^ and second estimated vehicle speed V r Based on the above, a vehicle torque corresponding to the driving force to be exerted by the electric vehicle as a whole is estimated for each driving wheel. For example, a first estimated torque T m1 ^ and the third estimated torque T m3 ^. Also, the total torque T m * For example, the vehicle torque is calculated based on the second estimated torque T m2 Then, the vehicle torque estimated based on the vehicle speed (first estimated torque T m1 ^ and the third estimated torque T m3 ^) and total torque T m * The vehicle torque (second estimated torque T m2^) and the deviation of df and the second drive wheel disturbance torque T dr ) is estimated.

[0163] In this way, the vehicle torque estimated based on the vehicle speed and the total torque T m * By calculating the drive wheel disturbance torque based on the deviation between the vehicle torque estimated based on and the vehicle torque estimated based on, a particularly accurate drive wheel disturbance torque can be estimated for each drive wheel. As a result, the vehicle disturbance torque T d Therefore, the estimation accuracy of the vehicle torque estimated based on the vehicle speed and the total torque T m * By calculating the drive wheel disturbance torque based on the deviation between the vehicle torque estimated based on and the vehicle torque estimated based on, the electric vehicle can be controlled particularly accurately regardless of changes in the wheel load of the drive wheels.

[0164] In the above embodiment and each modified example, the total torque T m * When is zero or positive, the maximum value of the estimated drive wheel disturbance torque for each drive wheel is equal to the vehicle disturbance torque T d It is estimated that the total torque T m * When is negative, the minimum value of the estimated drive wheel disturbance torque for each drive wheel is the vehicle disturbance torque T d That is, as shown in the above equation (44).

[0165] In this way, the vehicle disturbance torque T d When a change in the wheel load of each drive wheel causes one of the drive wheels to slip, the drive wheel disturbance torque estimated for the drive wheel that is not slipping (the so-called non-slip wheel) is calculated as the vehicle disturbance torque T d Therefore, even if the wheel load of each drive wheel changes, the vehicle disturbance torque T d As a result, the electric vehicle is controlled particularly accurately regardless of changes in the wheel load of the drive wheels.

[0166] In the above-described embodiment and each modified example, in particular, the driving wheel disturbance torque (for example, the first driving wheel disturbance torque T df and the disturbance torque of the second driving wheel T dr ) and vehicle disturbance torque T d Based on this, the distribution ratio K of the driving force to the driving wheels f3 is set, and this distribution ratio K f3 In accordance with this, the torque to be output by each of the plurality of electric motors is controlled.

[0167] In this way, the drive wheel disturbance torque and the vehicle disturbance torque T d Based on the allocation ratio K f3 By setting the torque distribution ratio, the driving force is appropriately distributed in accordance with changes in the wheel load of the driving wheels. Therefore, the electric vehicle is particularly accurately controlled regardless of changes in the wheel load of the driving wheels. d Allocation ratio K based on f3 As explained in the operation of the above embodiment, this setting is particularly effective in the stop control S13.

[0168] In the above embodiment and each modified example, the deviation of the drive wheel disturbance torque estimated for each drive wheel is calculated as the drive wheel disturbance torque deviation ΔT d is calculated. Then, this drive wheel disturbance torque deviation ΔT d and vehicle disturbance torque T d Based on the distribution ratio K f3 is set.

[0169] In this way, the drive wheel disturbance torque deviation ΔT d and vehicle disturbance torque T d Based on the allocation ratio K f3 By setting the above, when there is a change in the wheel load of the drive wheels, a particularly appropriate distribution ratio K f3 Therefore, the electric vehicle is controlled particularly accurately regardless of changes in the wheel load of the drive wheels.

[0170] In the above embodiment and each modified example, specifically, the vehicle disturbance torque T d Based on the first allocation ratio Kf1 is calculated, and the drive wheel disturbance torque deviation ΔT d Based on the second allocation ratio K f2 Then, the first distribution ratio K f1 and the second distribution ratio K f2 Based on the deviation of f3 is set.

[0171] As mentioned above, the first distribution ratio K f1 is the basic distribution ratio in an ideal state where there is no change in the wheel load of the drive wheels. df and the disturbance torque of the second driving wheel T dr When there is a difference in the wheel load of the drive wheels, the second distribution ratio K f2 is the distribution ratio K f1 Therefore, as mentioned above, the first distribution ratio K f1 and the second distribution ratio K f2 Based on the deviation of f3 By setting the appropriate distribution ratio K f3 As a result, the electric vehicle is controlled particularly accurately regardless of changes in the wheel load of the drive wheels.

[0172] In the above embodiment and each modified example, the estimated vehicle disturbance torque T d is used in the stop control S13. Specifically, the estimated vehicle speed (first estimated vehicle speed V f ^ and second estimated vehicle speed V r ^) based on the vehicle speed feedback torque T ω Then, the vehicle disturbance torque T d and vehicle speed feedback torque T ω Based on this, as the vehicle speed decreases, the vehicle disturbance torque T d The torque target value (second torque target value T m2 * ) is calculated. Then, this torque target value (second torque target value T m2 *) and determines whether the electric vehicle is about to stop. If it is determined that the electric vehicle is about to stop, the torque output by the electric motor (front motor torque T mf and rear motor torque T mr ) is the allocation ratio K f3 According to the second torque target value T m2 * The torque is controlled so as to converge to the distributed torque.

[0173] In this way, the estimated vehicle disturbance torque T d In the stop control S13, the electric vehicle can be stopped and maintained in a stopped state even if there is a change in the wheel load of the drive wheels, etc. In other words, the electric vehicle is controlled to stop particularly accurately, regardless of a change in the wheel load of the drive wheels, etc.

[0174] The above describes an embodiment of the present invention, but the configurations described in the above embodiment and each modified example only show some of the application examples of the present invention and are not intended to limit the technical scope of the present invention.

[0175] For example, the first estimated vehicle speed V f ^ and second estimated vehicle speed V r As a specific method for estimating the first driving wheel disturbance torque T^, a method other than the method described in the above embodiment can be adopted. In addition, the selector 77 used in the disturbance torque estimating unit 52 may use a calculation different from the calculation described in the above embodiment to estimate the first driving wheel disturbance torque T^. df and the second drive wheel disturbance torque T dr Based on the vehicle disturbance torque T d Similarly, the distribution ratio calculation unit 78 used in the disturbance torque estimation unit 52 can set the first drive wheel disturbance torque T df , second drive wheel disturbance torque T dr , and vehicle disturbance torque T d Based on the allocation ratio K f3 The same applies to the configuration related to the vibration suppression control S14, other configurations, calculations, etc.

Claims

1. A control method for an electric vehicle including a plurality of drive wheels and a plurality of electric motors that generate drive forces for the plurality of drive wheels, estimating a vehicle speed for each of the drive wheels based on a rotational speed of the electric motor; estimating, for each of the drive wheels, a drive wheel disturbance torque that is a disturbance torque acting on the drive wheels based on the vehicle body speed estimated for each of the drive wheels; estimating a vehicle disturbance torque, which is a true disturbance torque acting on the electric vehicle as a whole, based on the drive wheel disturbance torque estimated for each of the drive wheels; controlling the torques to be output by the plurality of electric motors based on the vehicle disturbance torque; A method for controlling an electric vehicle.

2. 2. A control method for an electric vehicle according to claim 1, Calculating a total torque which is the sum of torques to be output from the plurality of drive wheels; estimating the drive wheel disturbance torque and the vehicle disturbance torque based on the total torque; A method for controlling an electric vehicle.

3. 3. The method for controlling an electric vehicle according to claim 2, estimating, for each of the drive wheels, a vehicle torque that corresponds to a driving force to be exerted by the electric vehicle as a whole, based on the vehicle body speed estimated for each of the drive wheels; estimating the vehicle torque based on the total torque; The driving wheel disturbance torque is estimated based on a deviation between the vehicle torque estimated based on the vehicle body speed and the vehicle torque estimated based on the total torque. A method for controlling an electric vehicle.

4. 4. The method for controlling an electric vehicle according to claim 2 or 3, If the total torque is zero or positive, a maximum value of the drive wheel disturbance torque estimated for each of the drive wheels is estimated to be the vehicle disturbance torque; If the total torque is negative, the minimum value of the drive wheel disturbance torque estimated for each of the drive wheels is estimated to be the vehicle disturbance torque. A method for controlling an electric vehicle.

5. A control method for an electric vehicle according to any one of claims 1 to 4, setting a distribution ratio of driving force to the driving wheels based on the driving wheel disturbance torque and the vehicle disturbance torque; controlling the torques to be output by each of the plurality of electric motors in accordance with the distribution ratio; A method for controlling an electric vehicle.

6. 6. A control method for an electric vehicle according to claim 5, calculating a drive wheel disturbance torque deviation, which is a deviation of the drive wheel disturbance torque estimated for each of the drive wheels; setting the distribution ratio based on the drive wheel disturbance torque deviation and the vehicle disturbance torque; A method for controlling an electric vehicle.

7. 7. A method for controlling an electric vehicle according to claim 6, calculating a first distribution ratio based on the vehicle disturbance torque; calculating a second distribution ratio based on the drive wheel disturbance torque deviation; setting the allocation ratio based on a deviation between the first allocation ratio and the second allocation ratio; A method for controlling an electric vehicle.

8. 8. A method for controlling an electric vehicle according to claim 6 or 7, Calculating a vehicle body speed feedback torque based on the vehicle body speed; calculating a torque target value that converges to the vehicle disturbance torque as the vehicle speed decreases, based on the vehicle disturbance torque and the vehicle body speed feedback torque; determining whether the electric vehicle is about to stop based on the torque target value; When it is determined that the electric vehicle is about to stop, the torque output by the electric motor is converged to the torque obtained by allocating the torque target value in accordance with the allocation ratio. A method for controlling an electric vehicle.

9. A control device for an electric vehicle including a plurality of drive wheels and a plurality of electric motors that generate drive forces for the plurality of drive wheels, a vehicle speed estimating unit that estimates a vehicle speed for each of the drive wheels based on a rotation speed of the electric motor; a drive wheel disturbance torque estimating unit that estimates, for each drive wheel, a drive wheel disturbance torque that is a disturbance torque acting on the drive wheel based on the vehicle body speed estimated for each drive wheel; a vehicle disturbance torque estimating unit that estimates a vehicle disturbance torque, which is a true disturbance torque acting on the electric vehicle as a whole, based on the drive wheel disturbance torque estimated for each of the drive wheels; Equipped with controlling the torques to be output by the plurality of electric motors based on the vehicle disturbance torque; Control device for electric vehicles.

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